In this section, we present the numerical result for the Sivers function of the sea quarks \(\bar{u}\)  and \(\bar{d}\) .
To specify the values of the parameters \(g_1\) , \(g_2\) , \(\Lambda _{\bar{q}}\) , \(\Lambda _\pi \)  in our model, we try to fit the model result to the existing parameterizations for the distributions \(f_{1}^{\bar{q}/\pi }(x)\)  and \(f_{1}^{\bar{q}/p}(x)\) , since these unpolarized distributions have been extracted from experimental data and are well known.
In our work, we adopt the GRV leading-order (LO) parametrization [1]} to perform the fit for \(f_{1}^{\bar{u}/\pi ^-}(x)\)  (or \(f_{1}^{\bar{d}/\pi ^+}(x)\) ) as well as adopt the MSTW2008 LO parametrization [2]} for \(f_{1}^{\bar{u}/p}\)  and \(f_{1}^{\bar{d}/p}\) .
In the first fit, we can obtain the values of the parameters \(g_2\)  and \(\Lambda _{\bar{q}}\) ;
while in the second fit of \(f_{1}^{\bar{q}/p}\) , we can obtain the values of the parameters \(g_1\)  and \(\Lambda _\pi \) . In both fits, we fix the mass for the quark and the sea quark to be \(m=0.3~\text{GeV}\) .
